The story telling of Matthew of Jesus telling these stories has a fourfold structure that the parable of the sower of Jesus has.
3 καὶ ἐλάλησεν αὐτοῖς πολλὰ ἐν παραβολαῖς
24 Ἄλλην παραβολὴν παρέθηκεν αὐτοῖς
31 Ἄλλην παραβολὴν παρέθηκεν αὐτοῖς
33 Ἄλλην παραβολὴν ἐλάλησεν αὐτοῖς
That mirrors this:
4 καὶ ἐν τῷ σπείρειν αὐτὸν ἃ μὲν ἔπεσεν παρὰ τὴν ὁδόν
5 ἄλλα δὲ ἔπεσεν ἐπὶ τὰ πετρώδη ὅπου οὐκ εἶχεν γῆν πολλήν
7 ἄλλα δὲ ἔπεσεν ἐπὶ τὰς ἀκάνθας
8 ἄλλα δὲ ἔπεσεν ἐπὶ τὴν γῆν τὴν καλὴν
The explanation of this fourfold initial parable by Jesus for the disciples at their insistence allows Matthew to give special attention to this fourfold instructive story.
It also allows Matthew to give further attention to the fact that all Jesus taught this way he taught using parables. And that highlights this fourfold structure in Matthew's telling also. This is deeper than we can easily explicate. My own conjecturing is that Matthew considers it plowed ground literary ground that readers shouldn't quickly pass through or pass over without thinking about the ground of the parables and their/our own hearts for considering it/them profoundly as rather significant and generative.